Modified coumarins. 14. Synthesis of 7-hydroxy-[4,3?]dichromenyl-2,2?-dione derivatives

Dubovik, I. P.; Garazd, M. M.; Khilya, V. P.

doi:10.1007/s10600-005-0006-1

Cited by 4 publications

(5 citation statements)

References 15 publications

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“…This signal was not found in the C2 1 H NMR spectrum. All C2 NMR data were in accord with those previously reported for 2-(7-hydroxy-2-oxo-2 H -chromen-4-yl) acetic acid or 7-hydroxycoumarinyl-4-acetic acid [29].…”

Section: Resultssupporting

confidence: 85%

“…Nine synthetic coumarin analogs were submitted to the biotransformation experiments. All coumarins used as substrates were obtained according to known methods through a Pechmann reaction, and all of their spectroscopic data were identical to those previously described for 7-hydroxy-4-methyl-2 H -2-chromenone ( 1 ) [32], 5,7-dihydroxy-4-methyl-2 H -chromen-2-one ( 2 ) [33], 7,8-dihydroxy-4-methyl-2 H -chromen-2-one ( 3 ) [34], 7-hydroxy-2,3-dihydrocyclopenta[ c ]chromen-4(1 H )-one ( 4 ) [33], 7,9-dihydroxy-2,3-dihydrocyclopenta[ c ]chromen-4(1 H )-one ( 5 ) [33], 6,7-dihydroxy-2,3-dihydrocyclopenta[ c ]chromen-4(1 H )-one ( 6 ) [35], methyl 2-(7,8-dihydroxy-2-oxo-2 H -chromen-4-yl)acetate ( 7 ) [36], methyl 2-(5,7-dihydroxy-2-oxo-2 H -chromen-4-yl)acetate ( 8 ) [37], and methyl 2-(7-hydroxy-2-oxo-2 H -chromen-4-yl)acetate ( 9 ) [38].…”

Section: Methodsmentioning

confidence: 99%

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Mapping the Biotransformation of Coumarins through Filamentous Fungi

et al. 2019

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Natural coumarins are present in remarkable amounts as secondary metabolites in edible and medicinal plants, where they display interesting bioactivities. Considering the wide enzymatic arsenal of filamentous fungi, studies on the biotransformation of coumarins using these microorganisms have great importance in green chemical derivatization. Several reports on the biotransformation of coumarins using fungi have highlighted the achievement of chemical analogs with high selectivity by using mild and ecofriendly conditions. Prompted by the enormous pharmacological, alimentary, and chemical interest in coumarin-like compounds, this study evaluated the biotransformation of nine coumarin scaffolds using Cunninghamella elegans ATCC 10028b and Aspergillus brasiliensis ATCC 16404. The chemical reactions which were catalyzed by the microorganisms were highly selective. Among the nine studied coumarins, only two of them were biotransformed. One of the coumarins, 7-hydroxy-2,3-dihydrocyclopenta[c]chromen-4(1H)-one, was biotransformed into the new 7,9-dihydroxy-2,3-dihydrocyclopenta[c]chromen-4(1H)-one, which was generated by selective hydroxylation in an unactivated carbon. Our results highlight some chemical features of coumarin cores that are important to biotransformation using filamentous fungi.

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Section: Resultssupporting

confidence: 85%

Section: Methodsmentioning

confidence: 99%

Mapping the Biotransformation of Coumarins through Filamentous Fungi

et al. 2019

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“…This can undergo an intramolecular nucleophilic attack on the ester carbonyl inducing a cleavage of an acyl oxygen bond. Elimination of ethanol in this step leads to the formation of lactones (10)(11)(12)(13)(14)(15)(16)(17). During the present work we have been able to isolate and characterize the intermediate chalcone 12 by x-ray diffraction, which is formed during the reaction of 5,6-benzocoumarin-4-acetic acid and 3-ethoxy salicylaldehyde (Fig.…”

Section: Resultsmentioning

confidence: 91%

“…[11] Among the synthetic methods, the most plausible route has been the 4 þ 2 approach, making use of coumarin-4-acetic acids and salicylaldehydes, which has undergone several modifications. [12][13][14][15] Other methods establishing a C-C bond between coumarins make use of Ullmann condensation, ferrocyanide oxidation, [16] and Mn(III)-catalysed dehydrogenation. [17] Substituted hydroxyl biphenyls act as precursors in the construction of many bicoumarins.…”

Section: Introductionmentioning

confidence: 99%

Synthetic and Structural Studies on Novel 4,3′-Bicoumarins

Pujar

Kulkarni

Alawandi³

et al. 2015

Synthetic Communications

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A series of directly linked 4-3 0 bicoumarins have been synthesized by both Knoevenagel and Perkin reactions. This single-step transformation was accomplished by the reaction of coumarin-4-acetates with substituted salicylaldehydes in presence of piperidine using ethanol as solvent and by the reaction of coumarin-4-acetic acids with substituted salicylaldehydes in the presence of sodium hydride in acetic anhydride. Greater yields have been obtained in the sodium hydride and acetic anhydride condition. An intermediate chalcone with an ortho-hydroxyl group, which is a precursor for lactone formation, has been isolated and its structure has been confirmed by x-ray analysis. The nonplanar S-cis arrangement of two C4-C3' double bonds has been confirmed by nuclear Overhauser spectroscopy (NOE) and x-ray studies. The UV-fluorescence studies support the formation of a conjugated bicoumarin system.

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“…Bicoumarins, in which two coumarin ring systems are directly linked through a C-C bond, are a group of regio-isomers which are of synthetic interest (Ilyas & Parveen, 1996;Dubovik et al, 2004;Frasinyuk et al, 2012). Their natural occurrence and structural diversity originate from various positions of the linkage which can lead to pyran-pyran-linked bicoumarins, viz., 3-3 0 , 3-4 0 , 4-4 0 , or pyran-benzene-linked bicoumarins wherein the points of linkage are C3/C4 with the C5-C8 positions in the second coumarin moiety (Hussain et al, 2012).…”

Section: Chemical Contextmentioning

confidence: 99%